The Song They Wished Would Last Forever
by amethystkrystal
Summary: Struggling to cope with the loss of his grace, Castiel seeks refuge with the Winchesters. Weeks pass and Cas finds his relationship with Dean has developed into something neither of them could have anticipated. As matters become more complicated, Cas will have to make a choice between the tragic love of Dean Winchester and his long sought-after dream of peace in heaven.
1. Part One

PART ONE

It was days before Castiel finally came to them. After they were forced to let Crowley go. After the angels fell. Days of chaos and confusion passed before Castiel found his way to the door of the Men of Letters' bunker. He was forced to knock.

Dean greeted him with a splash of holy water to the face. When it had no effect, the oldest Winchester pulled Cas into a tight hug. "Cas…" Dean's gravelly voice whispered his name with emotions Cas couldn't quite figure out. He didn't sound angry, at least.

"Cas, where the hell have you been?" Dean pulled away, still not angry. Exasperated maybe? Concerned? Both? Cas wished human emotions were easier to read.

"I had to walk here," Cas snapped. He didn't mean to speak so harshly, but he was _tired_. "Metatron took my grace. He used it for a spell to make the angels fall."

Saying the words out loud made him realize it all at once, the absolute enormity of what had happened. He could feel the chill of the air around him and the uncomfortable itch of his growing facial hair. Dozens of new and horrifying sensations served to remind him of what he'd become, what he'd lost. Stripped and drained of the very essence of what he was, he felt raw. Naked. _Vulnerable._

"Wait so you're telling me you lost your mojo?" Dean looked at him with eyes full of pity, and Cas remembered something he'd said to him once, a long time ago.

_"Without your power you're basically just a baby in a trench coat."_

He was a baby now, a helpless child who knew nothing about the world he now found himself in. He throat started to close up, and he felt a tightness in his chest and stinging in his eyes.

_"You know who whines? Babies."_

Cas pushed Dean aside and stormed into the bunker. He found the closest bedroom and locked himself in it. A quick glance around told him the room belonged to Dean. Of course. He sat on the edge of the bed and buried his head in his hands, hating that he could feel the dirt and sweat that covered he skin and he couldn't just "mojo" it away. Wetness began to seep from his eyes and into his hands. The pains in his chest and throat forced him to release a choked, gasping breath.

Castiel, former Angel of the Lord, was crying for the very first time, and he could not stop.

He cried for everything. For the war and strife that had plagued heaven. For his brothers, slain by his own blade. For the havoc he wrought on Earth when he carried the Leviathans. For Sam and Dean and all the hurt he'd caused them. For letting Metatron destroy the angels. He cried for all the times he had tried to be righteous and failed catastrophically. His tears were his penance.

"Cas open up!" Dean rapped violently on the door, momentarily breaking Cas from his thoughts. "Come on man, let me in. It's my freaking room."

"Leave me alone, Dean!" Cas hated the way his voice sounded choked and broken.

"Cas, you know I _will _break this door down if I have to."

Cas had spent enough time with Dean to know he wasn't bluffing. Resigned, he opened the door. "What do you want, Dean?"

Dean shut the door behind him and crossed his arms. "You look like hell, man."

Cas narrowed his eyes. "I had to walk here through much wilderness."

"No that's not what I mean." Dean crossed the room and sat on the edge of the bed. Cas sat down beside him, and Dean looked at him carefully. "You've been crying?"

Cas shifted uncomfortably and looked down. He cheeks felt hot, yet another unpleasantly novel sensation. "It's never happened before."

He expected Dean to say something to him. Perhaps tell him to stop whining and "suck it up". What Cas did not expect, however, was for Dean to put his arms around him and pull him close.

"You'll be okay. We'll figure this out," said Dean, his mouth so close to Cas's ear that he spoke in a comforting whisper. "I promise you Cas, right here, right now, I promise you will get your grace back. No matter what it takes."

Cas couldn't explain it, but as soon as Dean's arms were around him, the tears started again. He wanted to say something, an apology or an explanation perhaps, but the words would not come and he could do nothing but sob. Acting on what felt like a sort of instinct, Cas let his forehead rest on Dean's shoulder. It was so uniquely human, the desire for touch. Dean's protective arms holding his torso, the soft fabric of Dean's jacket on his cheek…the feeling of being held – being _comforted_ – felt so right. It was as if he had shattered into pieces and Dean's embrace held them together, still in pieces but no longer scattered.

It felt like a very long time before Cas stopped crying, but even then, Dean did not stop holding him.

By the time Dean and Cas emerged from Dean's room, Sam was preparing dinner. Kevin Tran was in the kitchen too, pouring over the stacks of books he had piled on the little kitchen table. The prophet gave hive a friendly nod of acknowledgement and then lapsed back into his intense reading. Sam looked up from his cooking and flashed him a warm, genuine smile. Behind that though, Cas could sense pity in his gaze.

"Hey Cas, glad to see you're okay."

"Hello Sam." Cas was anything but okay, but he was alive, which was what Sam meant really.

"Dinner will be ready in few minutes, if you're hungry. Nothing special, just boxed mac and cheese."

"I'm famished actually. Thank you." It had been a long time since he'd eaten, not wanting to waste time trying to get food when he had to find the Winchesters. But now that the search for them was over, he felt a hunger in his stomach reminiscent of what Famine had plagued him with.

"Cas, when was the last time you ate?" Dean was looking at him, concerned.

"I found a dumpster a day or two ago," Cas said simply. He noticed the two brothers exchange looks. He asserted, "I didn't want to waste time. I had to find you."

"Dammit Cas," was all Dean said.

Dinner was a quiet affair. Sam and Kevin were curtly informed of Cas's lack of Grace, and Cas left them with the clear impression that he did _not _want to talk about it. So, after they caught Cas up on what had happened in his absence (Crowley gone, weird angel activity _freakin' everywhere_), they finished the meal in silence. After he had polished off the last bite of his enormous plate of macaroni, Cas realized how immensely tired he was. Adrenaline and mania must have kept him going all those days and nights he walked in search of the Winchesters, but it was fading and fatigue was beginning to set in.

"I think I need to sleep," Cas announced. His statement was met with bemused looks from everyone.

Dean sighed and stood up. "Come on, I'll show you one of the spare bedrooms, and you can get some shut-eye."

Cas followed Dean out of the dining room and down the hall to a small and simply furnished bedroom. The bed looked comfortable enough, though Cas really didn't have any standards to test that by. Slowly, he pulled back the covers and started to climb in.

"Hang on," Dean said. "I'll get you a pair of my old sweatpants and a t-shirt."

Cas tilted his head. "Why?"

"Because you can't sleep in a trench coat, Cas," Dean called as he left down the hallway.

At the prospect of new clothes, Cas shrugged off his trench coat and then began to unbutton his shirt. By the time Dean returned, his pants were around his ankles and all he wore were his thin, white boxers.

"Ah come on!" Dean shouted when he returned to the room. He averted his eyes from the almost-naked Cas. "Seriously?"

"What?"

"Dudes don't strip when they know other dudes are about to come in the room."

Cas threw Dean a puzzled look. Humans behaved so oddly when it came to their own anatomy, attaching all sorts of connotations to it. Dean was still looking pointedly at everything but him. He thrust a pile of clothes at Cas. "Here take these," he said. "You, uh, have a good sleep." He turned and hastily left the room.

Cas put on the clothes Dean had given him. He liked the softness of the material and familiar Winchester scent it carried, like alcohol and gunpowder. Satisfied by his new garments, Cas climbed into bed and laid on his back. He closed his eyes and waited. And then waited some more. He opened his eyes after a few moments, impatient. This was how it was done, right? He'd never actually slept before, but he'd seen Dean do it enough times. Just close your eyes and…wait? But Cas couldn't just let sleep come; every time he closed his eyes his mind wandered into discomforting thoughts about his present situation. Thoroughly annoyed, he kept changing positions in the hope that if he aligned his body in exactly the right way it would help him fall asleep faster. He was sprawled horizontally across the mattress, arms and legs dangling over the edge, when Dean came back in the room.

"Uh you okay, Cas?"

"I can't sleep," Cas said, not moving from his awkward sprawl.

"Have you tried counting sheep?"

"Dean, we don't have any livestock here."

Looking like he was trying to hold back laughter, Dean sat down on the bed next to Cas's legs. "Alright, talk to me. Why can't you sleep?"

"I don't know. I just can't," Cas said, looking over his shoulder at Dean. "I've watched you and Sam sleep many times, and it seems like all you need to do is close your eyes. What am I doing wrong?"

"Well for starters, laying like that isn't going to get you anything but a stiff neck," Dean said. He swung his legs up on to the bed and reclined back. "See you put your head on the pillow like this."

"I tried that. It didn't work," said Cas, annoyed. He shifted himself so that he was laying just like Dean, and they were shoulder-to-shoulder lying vertical on the bed. He squeezed his eyes shut, not feeling any more restful. "I still can't sleep, Dean."

"Well maybe if you took that stick out of your ass and relaxed a little, it would help. You don't have to be so freaking tense all the time," Dean replied. He closed his eyes and let out a deep sigh. Cas was intrigued by the sudden calmness in Dean's face; it was a dramatic change from his usual expression.

Cas closed his eyes, gently this time, and let out an experimental breath, mimicking Dean. He felt calmer, but he still wasn't sleeping. "Alright, I'm relaxed. Now how do I sleep?"

"Just let it happen, Cas," Dean said softly. "Try not to think about anything in particular. Just focus on how tired you are and how nice it feels to lie down…" Dean was silent for several moments after that. His breathing changed suddenly, and Cas realized he was snoring.

"Dean," Cas whispered. But it was to no avail; the older Winchester was sound asleep. Mildly annoyed, Cas decided to attempt Dean's last bit of advice. He let his fatigue overcome him. He let his weight sink into the mattress, enjoying the way it felt to just simply be. He let himself feel comfortable and safe with the familiarity of Dean beside him. He couldn't say when exactly, but at some point late into the night, Cas fell asleep to the sound of Dean's snoring.

Cas woke up with his head on Dean's shoulder and his arm draped across Dean's chest. Waking up, he decided, was not pleasant. He thought sleep was supposed to be restoring. So why did his senses feel dulled and his limbs lethargic? He groaned and nestled his forehead into Dean's shoulder, groggily unaware of what he was doing as he sought softness and comfort. Dean stirred, turning slightly so that his cheek now rested on the top of Cas's head. Still half-asleep, Cas settled further into Dean's touch. He shifted himself so that most of his side rested against Dean. It was then that Dean opened his eyes and realized who was beside him. He jerked away and scrambled to the other side of the bed, giving Cas a ruffled look.

"Cas."

"What?"

"Personal space."

"Oh." Cas gave Dean a considering look. Humans, he needed to remember, had unspoken boundaries. Using Dean's shoulder as a pillow, no matter how comfortable the material of his jacket felt against his sleepy face, apparently crossed one of said boundaries.

Dean cleared his throat, still looking flustered. "So, uh, breakfast?"

Later that morning, the four of them – Dean, Sam, Cas and Kevin – found themselves holed up in the Men of Letters' library looking for anything relevant to the predicament of thousands upon thousands of ancient celestial beings walking the earth. After breakfast, Cas learned the delicate rituals of showering and shaving, the latter activity leaving him with several thin cuts across his face. He had also changed into his favorite suit and trench coat, which Sam had so kindly laundered for him. In the library, Cas busied himself by reading texts in languages the others couldn't understand. He like the feeling of being useful, the reassurance that even without his "mojo", he wasn't just dead weight to Sam and Dean.

"I just had a thought," Sam said, breaking the long silence. He gave Cas a look that could have been apologetic. "If Cas is technically human now, that means he's susceptible to possession."

"Sammy's right," said Dean. He looked at Cas and pulled down the collar of shirt to reveal the anti-possession tattoo just under his collarbone. "Cas, you gotta get inked."

The idea was unsettling; a tattoo implied permanence. It meant that he wasn't getting his grace back anytime soon. If he accepted getting the tattoo, then in a way, he would be accepting his fall as his fate. He didn't want to give up this fight, not yet. And he didn't want the Winchesters to give up either. Would they stop trying if they began to realize retrieving his grace was a lost cause?

Sensing his reluctance, Dean attempted to reassure him. "Look, we're going to do everything we can to get your mojo back. This is just a precaution, alright?"

He stared back at Dean. Cas suddenly remembered Purgatory, and Dean's manic insistence that he wouldn't be left behind, despite all the reasons why it would have been the better idea. He remembered Dean's frantic grip on his hand when they reached the portal and the heart wrenching look on his face when Cas let go. Dean, he realized, would never give up on him.

"Alright," Cas said. "I will 'get inked', as you call it."

Sam and Dean exchanged relieved looks. From a small table across the room, Kevin piped up, "Dude, I do not envy you."

"See, it wasn't so bad. Kevin's just a little bitch," Dean said as they left the tattoo parlor hours later. Just the two of them had gone to get Cas tattooed. Sam and Kevin had stayed at the bunker to continue "nerding out", as Dean put it.

Cas just nodded at Dean's remark, idly brushing his fingers over the newly tattooed skin under his collarbone. The pain hadn't been as bad as he'd expected, but after Naomi, the sight of so many needles made his skin crawl. He was relieved to be in the Impala, driving away from that place.

"Hey there's a Wal-Mart not too far from here," said Dean after several long moments of driving in silence. "We should stop and get you some things."

"What things?"

"Clean underwear, for starters," Dean quipped. He glanced over at Cas, smirking, but Cas returned the look with a blank, unamused stare. He frowned, continuing. "There's some stuff you're gonna need while your human. New clothes, your own razor, a toothbrush…things like that."

"Fine." He looked away from Dean, staring pointedly out the window. The prospect of new clothes and toiletries served as a staunch reminder of the longevity of his human state. Like the tattoo, it suggested the possibility of permanence.

"Believe me, Cas," Dean said gently. "I know this sucks. I know you want your mojo back, but in the meantime, you have to realize that you're human now."

"Dean." Cas said slowly. "This entire time, I have done nothing but realize my humanity." He turned away from the window. "I realized it when I shed tears for the very first time. I realized it when I fell as asleep last night and woke up this morning. I realized it when I was getting a tattoo to ward off possession. Every single moment, I feel all these new sensations and emotions all at once, and I am very much aware that I'm human. I'm very much aware that I have lost everything_._"

"Not everything," Dean shook his head. "You still have me, Cas. Despite all shit you pulled and all the crap that's gone down, I'm still here. Sammy too." He took his eyes off the road for a moment and met Cas's stare. "Cas, I promise that I will do whatever it takes to get your grace back. I've never given up on you in the past, and I sure as hell won't start now."

Dean returned his attention to the road, but Cas continued to stare at him. He felt a lot of things in the moment. Fear and doubt still held in his heart, but he was grateful and relieved at Dean's words. He felt something else as well. He couldn't name it exactly but it likened attachment and trust.

He sighed and said softly, "Thank you, Dean."

A moment later, bullets shattered the windshield.


	2. Part Two

PART TWO

Before he even opened his eyes, the nauseating smell of antiseptic and incessant beeping of machinery alerted Cas that he was in the hospital. He stirred weakly, his entire body aching. Feeling someone's hand on his arm, he looked over to see Dean in the bedside chair.

"Cas?" Dean smiled at him, but it looked pained. Blood soaked the front of his shirt and a long strip of cloth wrapped around his arm appeared to serve as a makeshift bandage.

"Dean," Cas slurred, heavily medicated. "Wha'appened?"

"Someone shot us. A demon." Dean grimaced. "Two bullets, right through the windshield. One nicked my arm and then the other…well, you weren't so lucky. Stuck itself right above your heart. They had to do emergency surgery to get it out, and even then, the doctors didn't know until a few hours ago if you would make it." Dean looked at him anxiously, as if any minute the heart monitor was going to flat-line. Cas couldn't even fathom what the past several hours could have been like for Dean.

Broken and blurred memories suddenly flashed in his mind. One moment he was gazing out the window of the Impala, and then his chest was on fire. He remembered Dean crying his name as he pressed his hands against Cas's heart, trying to stop the ceaseless stream of blood. Just before he slipped into unconsciousness, a woman running across the street caught his attention. He was certain he'd recognized her.

"Dean!" he exclaimed, suddenly remembering. "It wasn't a demon who shot us. It was an angel."

"What? How do you know that?"

"Before I fell unconscious, I remember seeing a woman running away, the vessel form of Ariel."

"Are you telling me _The Little Mermaid _tried to gank us?"

"I don't understand the reference," Cas said, narrowing his eyes at Dean. "But I'm sure it was an angel."

Dean shook his head. "Sam played FBI and got a look at the traffic camera recording. The woman you're talking about, Sam said her eyes turned black and then she smoked out."

"Demons are possessing angels." Cas furrowed his brow. "This can only lead to catastrophe."

"Yeah thanks, Captain Obvious," Dean sighed, pulling out his cell phone. "I'm gonna call Sam and fill him in on your little revelation. You try and get some rest."

"Thank you for not letting me bleed out on the side of the road," Cas mumbled as he leaned back against his pillow, letting the drugs take on their tranquilizing effect. Just before he fell asleep, he heard Dean reply,

"Anytime, Cas. Anytime."

The weeks that followed were unlike anything Cas had ever experienced. Discharged from the hospital after just over a week, he returned to the bunker. Still recovering, he spent most of his time curled up one the couch near the living room fireplace as he decoded ancient texts from the Men of Letters' library. Once, Cas caught himself feeling something like contentment one night as sat in the glow of the fire with his book and he could hear Sam and Dean bantering from the kitchen. He felt himself becoming attached, yearning for his niche in this little family. The feeling scared him; he couldn't accept this place as his home. Heaven was his home. Despite everything, that was where he belonged, and he couldn't lose sight of finding his way back there.

Still, he could not deny that the weeks he spent in the bunker was among the happiest times in his life. A lot of it had to do with Sam and Dean and how they took the bunker and made it more than a place to do research and sleep. It was a home. Sam found an old recipe book in the library and cooked for them every night. Dean fixed up an old record player and took it upon himself to introduce Kevin and Cas to the wonders of classic rock music. Sometimes all four of them would watch movies so late into that night that they would wake up the next morning still sprawled on the couches.

It felt like family, and Cas was terrified.

One night he must have looked particularly flighty because after everyone else had gone off to bed and he in the living room still reading, Dean emerged from the kitchen with a case of beer and sat down next to him. He removed the caps from two bottles with practiced ease and handed one of them to Cas.

"Thank you, Dean," he said, taking a long sip.

"How's the, uh, you know…" Dean gestured vaguely to his upper torso. "Gaping hole in your chest."

"Fine," Cas said, not looking up from his reading.

"And, uh, how are you doing besides that?"

"Fine." He turned the page in his book.

"Cas, you're a shitty liar, you know that?" Dean sighed, taking a sip of his beer. When Cas didn't say anything, he pressed on. "Look, I know you're not fine, so talk to me."

"You don't often want to talk about feelings," Cas observed. "That's usually Sam's department."

"Yeah, you're right," said Dean. "I don't usually like chick flick moments, but for a while now you've been looking like you need to get something off your chest. So c'mon Cas, what is it?"

A long moment passed before Cas set his book down and met Dean's concerned stare.

"It's been almost a month since you promised me you'd help me get my grace back, and we've done nothing but sit in this bunker and read useless books."

"Cas, if you think I'm going back on my word –"

"Dean, I don't know what to think. I just know that I'm not getting any closer to getting my grace back. And every day I spend here, the more human I become and I'm afraid that…"

"That what?"

"I'm afraid that one day I'll be so changed that even if we do find my grace, I won't be able to go back from this."

"We don't know that for sure," Dean shook his head. "Cas, I won't let that happen to you."

"Dean, you would only make my fall to humanity happen faster."

"What do you mean?" Dean raised an eyebrow.

Cas paused, uncertain. He wanted desperately to tell Dean the truth, to make him understand. But even he himself didn't fully comprehend what he'd been feeling in the past few weeks. Still, perhaps Dean could make sense of it. Perhaps Dean would help him untangle the web of emotions that had been spun around his heart.

"Since I pulled you out of hell, you have been most important to me. I cared for you, even before I knew I was capable of it. I tore heaven apart to see you triumphant. You have changed me Dean. Because of you, I feel things and want things that I never could have anticipated. Even as angel, a creature supposedly stripped of compassion, you meant everything to me.

"But humanity has changed how I feel. You were always important to me Dean, but now I feel something different. It's something deep and powerful and joyful and solemn all at once. I know it's not something I could have ever felt as an angel, and the more time I spend with you, the stronger this feeling gets and I think it could be enough to drive me away from heaven forever."

"Dammit Cas." Dean's voice was soft, his eyes wide. "Are you trying to tell me that you're in love with me?"

Cas had known love in other forms: love for his brothers and sisters, love for his Father, love for the Winchesters. But this was beyond anything he'd ever felt.

"I think...becoming human changed my feelings for you into something more profound, and now yes Dean, I am in love with you."

The words stirred something in him, and before he really even knew what he was doing, Cas's lips pressed against Dean's in a chaste but desperate kiss. Dean stiffened as their lips touched, and Cas, suddenly realizing a serious line had been crossed, pulled back.

"Dean, I'm sorry. I shouldn't –"

His apology was silenced as Dean placed his hands on either side of Cas's face and closed the space between their mouths. Lips feverishly pressed together, Dean's hands seemed to touch Cas everywhere, running through his hair and brushing across his neckline and down his chest. Cas reciprocated with equal fervor, pressing his hands to Dean's hips and reclining back so that Dean leaned over him. Their lips had since separated as Dean trailed gentle kisses along Cas's neck and collarbone. Cas rested his forehead on Dean's shoulder, moaning softly in his ear. He came undone in the feeling of Dean's touch, euphoria blazing inside him every time he felt Dean's lips on his skin. Tightness beginning in his groin, he rocked his hips against Dean's and felt a similar hardness through Dean's pants.

Dean let out a low breath and pressed his forehead to Cas's. A long, still moment passed. It was silent except for their quickened breathing. Their faces were so close that Cas noticed Dean's lips had darkened. He ached to kiss him.

"Dean." The name escaped his lips in a soft breath.

Their eyes met and Dean's pupils were wide with lust. But behind that, Cas could see conflict. "Cas, have you ever wanted something so badly but you didn't even realize how much you wanted it until you actually got it?"

Cas didn't say anything, unsure of what Dean was trying to get at.

"I never believed it was possible for me to love someone," Dean continued. He closed his eyes, struggling for the right words. "Being a hunter, I never deluded myself into thinking I could find someone and be happy. Maybe it could happen for Sam, but not me.

"But these past four years with you have changed that. That feeling you described before, deep and powerful and joyful and solemn all at once? I've been feeling it too, Cas. And I never knew what it was until I heard it from you. I love you, Castiel, and I don't know how this is gonna play out for us but I'm sure as hell willing to give this, whatever it is, a try."

"I'd like that." Those words were his surrender; his grace was lost to him now.

Dean smiled at him and shifted himself so that his head rested on Cas's chest like a pillow. They fell asleep like that, limbs tangled and bodies pressed together.

Cas had no trouble sleeping that night.

They woke up to the sound of Kevin screaming in agony.

Dean was on his feet immediately, bolting down the hall toward Kevin's room with Cas right behind him. Sam was already at the doorway, and they looked inside to see Kevin writhing in his bed and clutching at his chest.

"What the hell is going on?" Sam ran at the boy and seized his shoulders. "Kevin!"

Kevin threw his head back and let out a chilling scream, the sound of it almost inhuman. Then he went quiet, slumping into Sam's arms. Sam shook him, but he remained motionless.

"Kevin! C'mon wake up! Kevin!"

Kevin did not move for a long time. Finally he stirred and pulled away from Sam's arms. Sitting up he looked directly at Cas, who was shocked to see the prophet's eyes were glowing with celestial light. His gaze struck something inside Cas, a sort of deep recognition, and he knew that it was not the prophet he was looking at but somebody else entirely.

"Oh look what has become of you, Castiel." The voice that spoke to him did not belong to Kevin. It was cold and piercing, like a plunge into freezing water.

"Who that hell are you? What did you do to Kevin?" Dean was beside him, his apprehensive gaze flicking between Cas and the creature before them.

"I am Jehovah, Lord and Father of All Creation. The Prophet is serving as my vessel."

It was overwhelming, the feeling of absolute familiarity that struck him when he looked at the presence before them. Even with his grace gone, every fiber in Cas's being resonated with sheer celestial power.

"Are you saying that you're _God?_" Dean scoffed, ever the skeptic. "As in capital-G God?"

"Yes." Father's icy voice was level, betraying no irritation at Dean's words.

Dean was shaking his head. "No, you can't be Him. He's gone and not coming back."

"I have not interfered with the affairs of this universe for a very long time. But the world now requires my intervention."

"Look, I don't care what you're trying to do," Dean said. "I don't believe for a second that you're freaking God."

"Dean." Cas turned and gave Dean a pleading look. "He's not lying."

"How can you know that, Cas?"

"Because I just _know._" He silently begged Dean to trust him, a desperate look in his eyes. They stared at each other, and something in his expression must have gotten through to Dean because he looked at Father with slightly less hostility.

"Alright, so let's say you are God. Then tell me this: why, after all the disaster that's happened – after literal Hell on Earth, after the freaking Apocalypse – do you chose now to show up?"

"I left the Earthly and celestial realms to exist together as they were fated to, in simultaneous interdependence and conflict. However, Heaven has been lost and Hell has fallen to absolute chaos. All the angels have been cast out and many have been possessed by demons, as you saw with Ariel. It is clear to me now that Heaven and Earth are incompatible, and so I intend to rebuild Paradise. The Gates of Hell will be shut forever, and I am going to restore the angels and seal away Heaven so that nobody may ever leave."

God stepped forward and took Cas's face in his hands. "Castiel, my child." A small smile played on his lips. "You are unique among your brothers and sisters. You have faith and compassion – you have heart. I have made you so for a reason. The archangels are dead, and Naomi's reign has ended. My new Heaven needs a king."

"You want me to be King of Heaven?" Cas said in a shocked whisper.

"That's right, Castiel. With Heaven and Hell sealed away, angels and demons will never again wreak havoc on this Earth. You saw what happened to Ariel. More angels will be possessed, more people will die. Take your place as ruler in Heaven, and all of humanity will be saved."

Cas was too stunned to speak. He had longed for this for so long, a chance to bring peace to Heaven and Earth, to make up for all that he'd done. He would have his grace back. Dean and Sam would be safe and happy, no longer forced to hunt nightmares. So much had been broken, but God was giving him the chance to repair it. All he needed to do was say yes.

Dean suddenly grasped his hand. He looked livid, eyes blazing. "Cas isn't going anywhere."

"This choice does not belong to you, Dean Winchester." God's eyes fell to their entwined hands. "You and Castiel were always meant to find each other. But I never imagined your bond would develop the way it has."

"Yeah, well, what can I say? I'm always exceeding expectations." Dean's sarcasm lacked its usual sting and he gripped Cas's hand even tighter.

God just shook his head and looked back at Cas. "I will give you three days to make your choice. On the night of the third day, I will come to you in your dreams and you will give me your answer."

Cas could only nod.

God sighed and looked at all three of them. "Of all my creations, I cherish humanity the most. You have to understand, I am trying to save you all. Look outside your bunker, and you will see a token of my good intentions."

Without another word, God closed his eyes. A moment later, Kevin's eyelids fluttered open. Gasping like he'd just emerged from underwater, he stumbled back onto his bed.

"What happened?"

"God just used you as his meatsuit. He had a special message for Cas," Sam said gently. "Are you okay?"

"My head feels like it's about to split open," said Kevin. "But I guess I could be worse, right?"

"That's the spirit." Dean clapped him on the shoulder. "Now come on, let's go see what this 'token of good intentions' is."

At first glance, nothing seemed to be amiss just outside the bunker. However, the scent of something burning had them walking to a field on the side of the road. It was there that they found their token.

Metatron's body lay sprawled on the sizzling grass, the charred imprint of angel wings extending from his back. Castiel regarded his fallen brother with solemn. Metatron had taken his grace and destroyed the angels. God had done right in killing him.

"My Father means well," Cas said. "Metatron was a menace to Heaven."

"Cas, you can't seriously be thinking about saying yes," Dean said quietly, a pained expression on his face.

"I…I don't know." As he stared at Metatron's lifeless body and Dean started clenching his fists, Cas felt like he was being torn in half. God's offer was the best thing for everybody, for the world, for the Winchesters. But, looking at Dean, he wanted so badly to make the selfish choice.

"Alright," Sam said. His eyebrows were furrowed, looking at Dean and Cas. "Um, so how about you two stay back in the bunker, let Kevin rest, and I'll take care of Metatron before the cops start poking around."

"Fine," Dean said, already walking back to the bunker. He was pointedly looking anywhere but at Cas.

Cas followed him, looking up at the morning sky. _Father help me._

Wisely, Kevin made himself scarce the moment they returned to the bunker, leaving Dean and Cas alone in the living room. Dean glowered at Cas, daring him to speak.

"Dean, I don't have a choice here."

"Don't give me that crap," Dean snapped. "How many times have we gone over this? There's always a choice, Cas. You don't have to say yes."

"You don't understand how important this is. For millennia, I have watched angels and demons destroy this world. And now I can stop it. I can save people. I can save you and Sam. I've never wanted anything more than this chance to make things right."

"You've never wanted anything else more than that?" Dean laughed dryly, shaking his head. "Funny, I got the impression last night that there was something else 'most important' to you."

At Dean's words, Cas snapped. He pushed Dean against the wall and pinned him with his arm. "Do not," he growled, "_ever _presume that the thought of losing you doesn't kill me."

"Cas, if you loved me you wouldn't even consider saying yes." Dean blinked rapidly; Cas could see tears beginning in his eyes. "I've lost so much, don't make me lose you too."

"I'm doing this for you." Cas pressed his hands harder into Dean's shoulders. _Why can't you just understand? _"Everything you have worked for since you were a child is what God offers us now. You won't have to hunt anymore. You won't have to fear for your life. If I stay, it will be nothing but fear and chaos. I couldn't live with bringing that upon the world, with bringing that upon _you._"

"I would gladly take a thousand years of fear and chaos as long as I had you with me."

"Dean –" His protestation was lost to Dean's sudden, fevered kiss. Cas's own body reacted immediately, wrapping his arms around Dean's neck and pulling them closer together. Dean's hands were desperate, trailing all over his body, and Cas lost himself to Dean's touch. He let go of thinking about God and his offer; all that mattered now was Dean's fingers on his skin. In one abrupt motion, Dean spun them so that he now had Cas pressed with his back against the wall. Eyes still locked on Cas, Dean went to his knees. The ghost of a mischievous grin cross his face as he removed Cas's pants and boxers.

Cas felt his body shaking as Dean's hand ran from his navel to the tip of his member. He was achingly hard now. Leaning forward, Dean placed his hands on Cas's thighs and made use of his tongue, running it along his shaft with just enough pressure to make Cas moan. Reflectively, Cas arched his back and tilted his hips forward, and he shuddered in surprise pleasure when Dean's lips closed around his dick. Dean was cautious in his inexperience, beginning slow and gentle, but Cas's sighs were encouraging and soon the movements of his lips and tongue turned passionate.

"Dean, I want…" Cas whispered, trembling as Dean's mouth moved with uninhibited fervor along his dick. He wanted to touch Dean and for Dean to touch him. He wanted Dean so close to him that nothing could pull them apart. "I want you. I want to lie with you."

Dean looked up at Cas, his eyes wide with understanding. He moved his mouth away and made to get up from his knees. Before he was even fully standing, Cas seized the sides Dean's face and kissed him. Lips pressed together, they stumbled to Dean's room.

"Take your shirt off, Cas," Dean said, shutting the door behind them and then starting to strip off his own clothes. Within moments, they were both completely naked. "Lie down on the bed."

Cas did as he was told, and then Dean was on top of him. The sensation of their bodies pressed together made Cas shiver. Even as they tried to forget, they knew that time was not on their side, and they craved each other's closeness. Desperate for the feeling of lips on skin, they spent a long time kissing each other all over.

They learned each other in these tender moments. When Dean's lips brushed against the inside of his thighs, Cas elicited a deep, throaty noise that he never imagined he was capable of. Then Cas planted kisses along Dean's neck, just behind his ear, and Dean's eyes rolled almost back into his head, breath caught in his throat. It was a strange thing, Cas thought, that two people could want each other so badly, and the more they held each other, the stronger the desire became. It was an insatiable fire that possessed them.

Cas was nearly at his peak when Dean removed a bottle of lube from his bedside table and slickened himself. Cas's heart hammered. He wanted this. Every piece of him screamed for Dean. But yet he was terrified. He'd never felt so far away from his grace.

Dean caressed his face. "Are you sure?"

Nothing was sure, not now. But all Cas knew was that he wanted Dean in all the ways he could have him.

"I want you."

With trepidation, Dean put one finger and then another inside of Cas, who's whole body shook with the act. He felt Dean's fingers against him, pressing and stretching him, and soon he was very, _very_ close. "Dean," was all he could manage to say.

Dean nodded, understanding. They shifted themselves so that Cas was on his back and Dean knelt between his legs. He leaned forward and gave Cas a long kiss. And then he was inside him.

Cas cried out, the pain more searing that he'd anticipated. But it was pure pleasure at the same time. As Dean started to move faster, Cas tilted his hips toward Dean and they found a rhythm. They moved as one, and it felt like nothing could break them. The whole world had gone away and there was nothing but Dean. The sound of his ragged breathing, the sight of his flushed, naked skin, the feeling of their bodies locked together as he was inside him…his senses were consumed by Dean. Time had stopped, but it must have been several moments before he reached his release. As he came, Cas clung to Dean's arms and his right hand pressed into the burn mark he'd left all those years ago.

Dean came moments afterward, and both spent, they curled up together under the blankets. They did not speak for a long time, so long that Cas thought Dean had fallen asleep. But, eventually, Dean's choked whisper broke the silence.

"I'm gonna miss you so much."

Dean's words, Cas realized, were words of acceptance. The arguing was over.

"I'll miss you as well."

With wetness in his own eyes, Cas reached over and wiped the tears from Dean's cheeks.


	3. Part Three

PART THREE

They spent the rest of that first day in bed.

Sometimes they had sex. Their frantic desperation had quelled since that first time, and making love became slow and lasting. Finding their favorite parts of each other and lingering there, they learned to play each other like instruments. Each time, they became better at pulling all the rights string, and Cas wished their song could last forever.

Sometimes they had sex. But mostly, they talked.

They talked about each other and how what began as a rescue mission to Hell had turned into the two of them lying together in bed, confessing broken truths as tears stung in their eyes.

_"I used to be sickened by how much I cared about you, Dean. Angels are taught that they are superior to humans, but when I looked at you, I couldn't help but doubt that."_

_ "Even after everything you did– working with Crowley, the Leviathans, Naomi – I wanted you with me. It went against all logic and reason, but I couldn't stand to lose you. Once I said to Sam, 'If anybody else pulled that kind of crap, I would stab them in their neck on principle. Why should I give him a free pass?' His answer was the simplest thing: 'Because it's Cas.' I didn't really see his point at the time, but now I know exactly what he meant. He was talking about unconditional love."_

They talked about the lives they would have without each other.

_"I have a great deal of faith in my Father's plan. The idea of a fresh start is a good one. But I'm afraid for my reign. I can't fail Heaven again, not when so much is at stake."_

_ "I'm gonna make sure Sam's happy. That's the only good thing that's gonna come out of this, the only reason I'm letting you go through with this, really. I want Sam to find a nice girl and get married and have a house and a nice apple pie life. I'm gonna miss him like hell, but he's all I'm going to have in this world and I'll be damned if I can't give him the life he deserves."_

And then, just before falling asleep, they made their promises to each other.

_"I have lived a thousand lifetimes, Dean, and I will live for many more. The time we spent together will become no longer than a millisecond in the vast span of my life, but know that even after eons pass and the Earth is nothing more than stardust, I will not have forgotten the love we had."_

_ "Cas, you will be with me in every moment of my new life. You'll be my first thought when I wake up and my last thought when I go to bed. You'll be the loneliness I'll feel when I'm driving alone at night. You'll be the voice telling me to make it through one more day. Even after years have passed and I don't remember the sound of your voice or what it felt like to fall asleep next to you, I will still love you. And I'll be praying, every night. Even if you can't hear me."_

The second day was spent with Kevin and Sam.

They watched a lot of TV, ate a lot of Sam's cooking and Dean tried to crack a lot of jokes. It was a phantom version of the family sentiment Cas had once feared. It was ironic now how much he wished he could have this life with the Winchesters forever.

Sam had started out as nothing more to him than a way to get closer to Dean, but as time went on, Cas grew closer to the younger Winchester. They understood each other in a way that Dean never seemed to grasp; they both knew what it was like to have their good intentions twisted. In moments when Dean was so hurt that he couldn't even look at Cas, Sam was always kind to him. Cas was going to miss him.

Late that night, when he was in his room getting changed for bed, Cas heard Sam and Dean talking from the living room. They spoke in hushed voices, but Cas still caught some snippets.

_"I always knew you loved each other."_

_ "Yeah? How could you tell?"_

_ "You always came back to each other. Even when the universe seemed to be trying to keep you apart."_

They took a long drive on the third day.

Just the two of them, Dean and Cas set out in the Impala just after sunrise. Cas didn't know where they were going; Dean just said he wanted to take him for a drive. The ride along the rural highway was quiet. They didn't need to speak; they'd already said everything they needed to. All they wanted was each other's presence. Dean drove with one hand on the wheel and Cas held the other.

In the early afternoon, they stopped to eat at a little diner. Cas's last meal consisted of chicken tenders and a large slice of sweet cherry pie that he split with Dean. As he was finishing his last bite of syrupy crust, Dean started to laugh.

"What is it?"

"Nothing," Dean said, shaking his head but still laughing. "I just realized that this is our first date."

_And it's our last, _Cas almost said.

Dean's destination, it turned out, was a lake. They followed a long, winding road through the woods, and Dean parked the Impala in an area of gravel near the shore. Thick clusters of foliage ringed around the blue water, the leaves moving gently in the wind. The fast approaching sunset filtered through the evergreen trees, making the water seem to glitter. If the new Heaven was to have a Garden, Cas wanted it to look like this.

It was beside this lake that Cas discovered, out of all the times he'd been with Dean, he liked sex in the Impala the most. Sprawled across the backseat, Cas let Dean ravage him. They lasted a long time, almost seeming to move in slow motion as they savored every touch, every kiss. As the sun disappeared below the horizon, they came together and held each other close afterward, trembling and whispering "I love you" over and over again.

Dusk turned to darkness as they laid together like that. Cas listened to the sound of crickets, nestling his head against Dean's shoulder. He wished time would stop. He wished he could lay in Dean's arms forever. But that wasn't possible; his tired, heavy eyelids reminded him of that fact.

"I'm going to fall asleep soon."

Dean looked at him, his expression shattered. He kissed Cas full on the mouth for a long time. When they parted from their last kiss, Cas saw tears fall from Dean's eyes.

"Cas." Dean's voice cracked, and that sound alone was almost enough to make Cas change his mind right then. Curled up against him, he could feel the sobs that shook Dean's body as he took Cas in his arms. He knew these last moments would be difficult, but he never imagined his heart could feel this much pain.

"Good-bye, Dean. I love you." The words felt like a stab to the chest. His hand rested on Dean's arm. Closing his fingers around the branded handprint, Cas let his eyelids fall.


	4. Part Four

PART FOUR

Cas's body was gone when Dean woke up the next morning. All that remained of him were the discarded clothes he'd left strewn all over the inside of the Impala. Dean broke down sobbing as the remembered the night before. The tender way their hands had been on each other, the feeling of their bodies melded together as they waited for awful sleep.

_Good-bye, Dean. I love you._

Dean scrambled to put his clothes on and get out of the Impala. He couldn't take being naked anymore, not when Castiel's smell still ghosted the interior, his forgotten clothes draped all over the seats. As an afterthought, Dean took Cas's trench coat and wrapped himself tight in it. The heavy, oversized material almost felt like Cas's arms around him. Almost. He fell to his knees outside on the gravel and looked up, tears blurring his vision of the rosy morning sky.

"Castiel, I don't know if you can hear me. But I'm gonna talk anyways," Dean whispered to the clouds. "I woke up this morning without you, and I know that's how it's gonna be every morning and just the thought of that makes me never want to wake up again. But I hear your voice telling me to keep going, so I guess that's what I'm going to do."

Even after he finished his prayer, Dean's eyes remained trained on the sky. He wished he could feel something, _anything_, that told him he was connected to Cas, but his heart was hollow now. As he looked up, the clouds shifted and revealed the sun's light. A brilliantly clear rainbow suddenly appeared across the sky. The iridescent sun shined behind it like a halo.

_I have lived a thousand lifetimes, Dean, and I will live for many more. The time we spent together will become no longer than a millisecond in the vast span of my life, but know that even after eons pass and the Earth is nothing more than stardust, I will not have forgotten the love we had._

Dean blinked back his tears and smiled at the divine symbol of promise that arced across the clouds above him.


	5. Epilogue

EPILOGUE

Fifty-two years after Cas had left, Dean was lying in the hospital in the aftermath of a stroke. He closed his eyes for one moment, and when he opened them again, a tall, blonde woman in a black pantsuit stood at his bedside. The Reaper offered her hand to him and he took it without argument. His only regret was that he never gave Sam a proper good-bye.

At the Reaper's touch, the world shifted around him. The hospital room became the Impala hurtling down a stretch of highway with him at the wheel. An ancient Lynyrd Skynyrd song played over the radio. A quick glance in the rearview mirror told him that he was thirty years old again.

Dean's heaven was the open road.

He hadn't travelled this particular road in over fifty years, but somehow, he knew exactly where he was going. He came to long, dirt road that twisted through thick woods and led him to a lakeshore. It had been years but the sight of this place made his chest tighten. He parked on the area of gravel and walked out of the car. The sun was high in the sky, casting glimmering light on the calm water. Dean stood at the edge of the lake, watching the gentle waves as a thousand memories came back to him.

"Dean," a low voice said behind him. His heart seized at the sound of a voice he had not heard in decades.

He turned and saw Castiel standing behind him, next to the Impala. Brown hair hastily combed, eyes narrowed in contemplation and the all-too-familiar trench coat around his shoulders, Cas looked exactly as he had fifty-two years ago. Except for one thing. Massive, ebony wings extended from his back, sunlight glinting off the downy feathers.

All Dean could do was stare; unable to find the words that would fill in years of silence. Eventually, he managed to gasp, "Cas."

And then they ran to each other. They kissed, long and greedily, and held each other for a long time, whispering broken words of how much they had missed the other. Cas let his wings unfurl completely, wrapping them around Dean. After a few moments, they laid down beside each other at the lake's edge, hands clasped together. They told each other fifty years' worth of stories.

Cas talked about the peace in Heaven. Ruling was a difficult task fraught with consequences for every action he took – both the good and the bad. But slowly, he'd learned the delicate balance between compassion and justice, and the angels became a family again under his watch.

Dean told him about the family he'd built as well. Sam married a woman named Julia who was a librarian by day and a sci-fi movie junkie by night. She was funny, smart and endlessly understanding of the troubles the brothers buried. Dean had filled the voids in his heart with love for his three nieces. For many years, they'd all lived together in the same house with Uncle Dean having his own private upstairs apartment. A hunter can never really move on from his old life, but living with Sam, Julia and their daughters, he'd come pretty close.

They made love after telling their stories. It was surprising how, even after all the years between them, they still knew exactly how to bring each other to the edge. Cas's body was seared in Dean's memory and Dean's in his. They started dizzyingly with rough, impatient hands that clamored for each other, but they soon slowed into a rhythm of gentle touches and savored kisses. The sun was beginning to disappear behind the trees by the time they had finished.

They fell asleep together, lulled by the sound of water lapping on to the shore. It was the first of the infinite days they spent in Heaven together.


End file.
